<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width,initial-scale=1.0,minimum-scale=1.0,maximum-scale=1.0,user-scalable=no">
    <title>mypro1</title>
  </head>
  <body>
    <div id="app"></div>
    <!-- built files will be auto injected -->
  </body>
  <script>
    (function(){
      function change(){
        let winw = document.documentElement.clientWidth || document.body.clientWidth;
        document.documentElement.style.fontSize = winw*100/750+'px';
        console.log('1rem='+winw*100/750+'px')
      }
      change();
      window.onresize=function(){
        change()
      }
    })()
  </script>
</html>
